This allows for adding and removing of characteristics and descriptors after initial setup of the server.
When used it will send a service changed notification to all clients.
The changes will not take effect until all clients have disconnected and advertising restarted.
This allows creating instances of services/characteristics and decriptors without
needing to call the parent createX() methods. This allows creation of the attibutes
within a class or other structure and the attributes can be linked to the parent by
calling the parent addX() method.
Additonally this increases the backward compatibility with the original bluedroid library
to further support user migration.
* Add method to get all characteristics of a service
* Added method on NimBLEDescriptor to get the value out as a std::string
* Added methods to get things by handle where UUID could be used already.
* Added helper methods for getting a list of characteristics with a given UUID and service
* Demote the warning log for adding duplicate characteristics to a debug level log.
* Add methods to get services and characteristics using UUID + index
Server: Add onSubscribe() callback for characteristics.
Adds a new method to NimBLECharacteristicCallbacks that gets called when a client
changes it's subscription status.
* Remove NimBLE2902 class.
As the NimBLE2902 class usefulness was only related to callback functions that were replaced
by the NimBLECharacteristicCallbacks:onSubscribe() method this removes the NimBLE2902 class and
moves all subscription handling to NimBLECharacteristic.
* Update documents and examples to reflect this change.
* Add getSubscribedCount() to get the number of subscribed clients.
* Use critical sections to access characteristic/descriptor value data.
* Remove unnecessary code
* Create characteristic semaphore only if needed for indications.
* Fix advertising when not broadcasting a service.
This allows NimBLE options in menuconfig to reduce code size based on
the roles selected (scan/advertising/central/peripheral).
Significant code space can be saved by removing unnecessary roles for the application.
